Possible bad ECU? Or what?...

[91AwdEagleTalonTSI]

Hey guys , so this has been an on going problem now that it's started getting cold out.

So recently with the weather change I've been experiencing problems..

Here they are..
Takes a good 10 minutes to start even when pushing the gas in then popping it when the key is turned to start. But starts first crank every time if it is warm or has been started within 4 hours.

Slight misfire every now and then.

Stalls but is sporadically and tends to not do it if I have the heat/air on as long as the fans are spinning.

Runs rich . And horrible MPG (I've stayed out of boost as much as possible and it is still horrible)

I've been told by my mech. that a new ECU is 800?! When i've seen them for like 200 so I am trying to dodge that bullet. Others have said it could be an upstream o2 sensor. There is a check engine code but it is every now and then and its for the CTS. I have no clue what it is, please help.

Thanks guys

 

[91AwdEagleTalonTSI]

Also I can hear my fuel pump only turn on when the motor is actually on ; other than that I can't hear it prime when the key is turned and the car is not on. Can't hear it start pumping until the car is started.

 

[steve]

Also I can hear my fuel pump only turn on when the motor is actually on ; other than that I can't hear it prime when the key is turned and the car is not on. Can't hear it start pumping until the car is started.

That's not surprising. If you look at the wiring diagrams or read the tech manual you'll find that the fuel pump on a 1G is activated from the starter circuit (while key is in START position) and while the ECU is seeing CAS pulses. It doesn't turn on when you turn the ignition on. (unless it sees a glitch on the CAS signals from powering the CAS up) There is no need to prime, the system comes up to pressure as soon as the pump starts running. If it doesn't you have a leak in the fuel system somewhere. It also holds pressure for a pretty long time so running into a store and then restarting takes even less time to pressurize.

 

[DSM1G90]

Could have a bad check valve in the fuel pump, where this will cause the immediate loss of pressure in the fuel rail and line. This will make for long starts until it catches.

Wonder if one can add a check valve in the fuel line to keep some pressure up in the rail before the FPR allows the fuel to go back to the tank...

Been there with a bad TS - bad hot starts and similar and an occasional CEL. Replaced that bad boy and off and running.

'Til recently with some bad 'bucking and snorting' going on to almost dying on the freeway: bad and loose ground ground connections along with loose positive connections, esp from the white wires running back to the key. Got them all super tightened up and off and running again.

Something to check out as well - clean and tight connections to the battery.

-DSM

 

[Seamus]

Just a note, of it is bad wiring or connector at the coolant sensor, which os common. u don't need to track down a new plug. Just wire on female plugs.

 

[91AwdEagleTalonTSI]

Problem Solved for the hard start; CTS/CTS wiring brittle and hard to have current. Still runs semi rich sometimes tho. Not sure why.